# how many animals? **URL:** \ **Category:** Factual Questions\ **Created:** [August 15, 2001, 10:38pm UTC](https://boards.straightdope.com/t/how-many-animals/76458 "2001-08-15T22:38:52Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![megasad](https://avatars.discourse-cdn.com/v4/letter/m/eb8c5e/32.png) [@megasad](https://boards.straightdope.com/u/megasad)\ **Post date:** [August 15, 2001, 10:38pm UTC](https://boards.straightdope.com/t/how-many-animals/76458/1 "2001-08-15T22:38:52Z")
How many different types of animal are there in the world right now? I’m talking insects, mammals, fish, reptiles, Everything. How many species? I asked a biology teacher in my school a few months back but he didn’t know the answer. Also, how many have there been? Since I imagine a whole load of them have become extinct… Um, so if you want to divide the totals up into categories as well, that’d be appreciated. ---
**Author:** ![bibliophage](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bibliophage/32/7615_2.png) [@bibliophage](https://boards.straightdope.com/u/bibliophage)\ **Post date:** [August 15, 2001, 11:28pm UTC](https://boards.straightdope.com/t/how-many-animals/76458/2 "2001-08-15T23:28:43Z")
I don’t know exactly, but a number of [google](http://www.google.com) searches turns up several estimates. insects: 1-10 million, most have not yet been studied fish: 20-25 thousand birds: 8-10 thousand reptiles: 6-8 thousand mammals: 4-5 thousand ---
**Author:** ![wevets](https://avatars.discourse-cdn.com/v4/letter/w/e9a140/32.png) [@wevets](https://boards.straightdope.com/u/wevets)\ **Post date:** [August 16, 2001, 12:06am UTC](https://boards.straightdope.com/t/how-many-animals/76458/3 "2001-08-16T00:06:45Z")
There are anywhere from about 2 million to 30 million species currently living on Earth, depending on whose estimate you believe. A bit less than 2 million species have been identified, as bibliophage pointed out, most of which are insects. I have no idea on how many extinct species there are (were?), and I’ve never heard an estimate. I’d imagine it would run into the billions. ---
**Author:** ![wevets](https://avatars.discourse-cdn.com/v4/letter/w/e9a140/32.png) [@wevets](https://boards.straightdope.com/u/wevets)\ **Post date:** [August 16, 2001, 12:42am UTC](https://boards.straightdope.com/t/how-many-animals/76458/4 "2001-08-16T00:42:06Z")
Oops. That “…bit less than 2 million” includes plants as well as animals. Take off a bit for all the Plants, Fungi, Protists, Archaebacteria, and Eubacteria included in that figure. Without information in front of me, I don’t really know how many. ---
**Author:** ![Darwins\_Finch](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darwins_finch/32/20304_2.png) [@Darwins\_Finch](https://boards.straightdope.com/u/Darwins_Finch)\ **Post date:** [August 16, 2001, 12:44am UTC](https://boards.straightdope.com/t/how-many-animals/76458/5 "2001-08-16T00:44:28Z")
For reptiles, you can check [here](http://www.embl-heidelberg.de/~uetz/families/taxa.html). This will give you a breakdown of everything from Class downwards. Of course, this only details the reptiles we know about. [This page](http://www.embl-heidelberg.de/~uetz/db-info/SpeciesStat.html) from the same site puts the number of extant reptile species at 7971. [This site](http://ebooks.whsmithonline.co.uk/encyclopedia/76/A0000076.htm) gives some “big picture” numbers, and pretty much says what **bibliophage** said. [Here](http://www.swishweb.com/Animal_Kingdom/Birds/animal02b.htm), you can find a breakdown of bird species, and going backwards a few links will get you to fish, insects, reptiles, amphibians, and mammals as well. I’ll leave it as an exercise to the reader to add up all those damn numbers. As for extinct critters, a good starting place would be [here](http://www.ucmp.berkeley.edu/help/taxaform.html). ---
**Author:** ![Slip\_Mahoney](https://avatars.discourse-cdn.com/v4/letter/s/e47774/32.png) [@Slip\_Mahoney](https://boards.straightdope.com/u/Slip_Mahoney)\ **Post date:** [August 16, 2001, 12:50am UTC](https://boards.straightdope.com/t/how-many-animals/76458/6 "2001-08-16T00:50:45Z")
It’s been estimated that well over 90% of the species that have ever lived are now extinct. And there are more species of beetles than all other species combined. Which is what led Haldane to remark that “God seems to be inordinately fond of beetles.” ---
**Author:** ![Darwins\_Finch](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darwins_finch/32/20304_2.png) [@Darwins\_Finch](https://boards.straightdope.com/u/Darwins_Finch)\ **Post date:** [August 16, 2001, 1:00am UTC](https://boards.straightdope.com/t/how-many-animals/76458/7 "2001-08-16T01:00:38Z")
> [@](#): > > \*Originally posted by Slip Mahoney \* > **It’s been estimated that well over 90% of the species that have ever lived are now extinct.** Actually, A. S. Romer (in 1949) and Gaylord Simpson (in 1952) put the number closer to 99%! ---
**Author:** ![evilhanz](https://avatars.discourse-cdn.com/v4/letter/e/ba8739/32.png) [@evilhanz](https://boards.straightdope.com/u/evilhanz)\ **Post date:** [August 16, 2001, 3:50am UTC](https://boards.straightdope.com/t/how-many-animals/76458/8 "2001-08-16T03:50:31Z")
> [@](#): > > \*Originally posted by Darwin’s Finch \* > \*\*put the number closer to 99%! \*\* For those slow in math, that would put the estimate of the number of species that have ever lived on Earth up around 300 million, using the conervative estimate of 2 million identified species currently inhabiting this planet, with perhaps another 1 million unidentified. ---
**Author:** ![mmmiiikkkeee](https://avatars.discourse-cdn.com/v4/letter/m/edb3f5/32.png) [@mmmiiikkkeee](https://boards.straightdope.com/u/mmmiiikkkeee)\ **Post date:** [August 16, 2001, 10:47am UTC](https://boards.straightdope.com/t/how-many-animals/76458/9 "2001-08-16T10:47:53Z")
I’ve heard that it’s closer to 99% of all species that have lived on Earth are now extinct. It would be interesting (but practically impossible to do) to find out what proportion of species say in the last few hundred years we’ve had a direct role in exterminating. ---
**Author:** ![Darwins\_Finch](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darwins_finch/32/20304_2.png) [@Darwins\_Finch](https://boards.straightdope.com/u/Darwins_Finch)\ **Post date:** [August 16, 2001, 8:52pm UTC](https://boards.straightdope.com/t/how-many-animals/76458/10 "2001-08-16T20:52:14Z")
[Here](http://newton.physics.wwu.edu:8082/jstewart/scied397/brian.html) is another site which has some numbers for extinctions. From this site: > [@](#): > > However, documented cases since c. 1600 have found that 484 animal species and 654 plant species have become extinct. (Global Biodiversity Assessment, 1995) This number is well documented and verifiable and it is well above the projected background rate. Again, this only counts those species which we know of - many more could have been driven to extinction without our ever knowing about them.